The vertebrate central nervous system (CNS) forms from a population of multipotent progenitor cells that generate all mature neurons and glia. These cells are particularly important for the treatment of injury and disease, but in most cases they are not maintained in adult CNS tissues. The mechanisms responsible for CNS progenitor maintenance are poorly understood, and the goal of this research proposal is to define and examine a new molecular pathway underlying this process. This work will investigate the role of a specific transcriptional regulator, Tcf3, in maintenance of zebrafish spinal cord progenitors. Tcf3 regulates progenitor and stem cell state in other epithelial tissues, but its function in the CNS is unknown. Specifically the proposed experiments will test the hypothesis that Tcf3 acts both transcriptionally and epigenetically as a master regulator of the progenitor state in the embryonic spinal cord. First, the capacity of Tcf3 to maintain spinal progenitor multipotency, self-renewal, and gene expression will be tested. Second, specific genes obtained from a microarray analysis in tcf3 mutants will be assayed to determine which have altered expression in spinal progenitors, and their function in spinal progenitor maintenance will be determined. Third, the function of DNA methylation in progenitor maintenance downstream of Tcf3 will be assayed. Together, the work proposed here will lead to a new model for CNS progenitor maintenance, by identifying novel genes and molecular mechanisms that preserve multipotency and self-renewal. Our findings will help exploit CNS progenitors for the future treatment of neurological injury and disease.